This invention relates to devices for conducting diagnostic tests and methods for using such devices. In particular, it relates to disposable diagnostic test devices, and methods for use of such devices.
Advances in medical science have increased the need for clinical laboratory testing. The number of clinical laboratory tests performed is rapidly increasing every year. New tests and testing procedures are also expanding each year.
The medical field has relied on the clinical laboratory to perform these tests. Clinical laboratories depend on highly trained technical personnel and expensive equipment to perform the many tests needed by the medical community.
There is an ongoing need for disposable diagnostic products that reduce the complexities of operation and that can be used outside of the clinical laboratory, such as in the physician""s office, emergency room, operating room, and at home. In addition, there is a continuing interest in performing individual tests in these localities. Desirable features for testing in these environments include operational simplicity, precision, reproducibility, relatively low costs, and increased safety in sample handling. It is desirable to have a disposable device that can be used for individual testing in these environments to meet these needs.
This invention provides a disposable diagnostic device used for conducting diagnostic tests, such as immunoassays, and a method for using this device to conduct such tests that can be performed outside of a clinical laboratory. The device is relatively easy to use and inexpensive to manufacture since it can be made using, for example, a simple lamination process. Formed within the device are multiple chambers used to conduct the diagnostic test. These chambers include a channel, through which a solid phase moves by application of a peristaltic force. Successive diagnostic fluids, such as reagents and washes, are then moved to and displaced from the solid phase, also by way of peristaltic forces. The solid phase is eventually moved to a region of the channel from which a test result is read.
In one aspect, the invention features a disposable diagnostic device for conducting a diagnostic test on a sample. The device includes a substantially planar, flexible article, a channel formed within the article, at least one fluid-receiving compartment formed within the article and fluidly connectable to the channel, and a solid phase movably positioned within the channel. The article is xe2x80x9cflexiblexe2x80x9d in that the channel and fluid-receiving compartments within the article are sufficiently deformable to permit application of functional peristaltic forces as described below. Typically the entire article is fashioned from flexible material, although this need not be the case as long as the portions of the article defining the channel and compartments are sufficiently deformable.
In one embodiment, the article is a laminate, for example a laminate formed from two substantially planar, flexible sheets laminated together. A plurality of such articles can be manufactured as a continuous sheet capable of being wound into a roll. Users can easily remove individual articles from the roll by tearing at designated tear points, by cutting or by any other appropriate means of separation.
In yet other embodiments, the device includes a plurality of compartments formed within the laminate, also fluidly connectable to the channel. These compartments can be pre-filled with a fluid or empty, and can be aligned on opposite sides of the channel. The pre-filled compartments typically are filled with reagents and the empty compartments configured to receive waste fluids. The pre-filled compartments can be isolated from the channel by breakable seals. The solid phase can be manufactured from various materials, in various forms including without limitation beads, disks, stars, cubes, rods, and spheres.
The diagnostic device may be configured for application of a first peristaltic force for moving the solid phase along the channel, and for application of a second peristaltic force for moving fluid from the pre-filled compartment to the solid phase and from the solid phase to the empty compartment. As the fluid moves to and from the solid phase, the fluid movement can change direction along the solid phase as the solid phase moves along the channel.
In another embodiment, the channel may also include a sealable input port for application of a sample to the solid phase. A sample transfer device, that may be removable, and which is fluidly connectable to the input port for applying a predetermined quantity of sample to the solid phase, may also be included as part of the device. In addition, the channel can include an air vent that is connectable to an external source of gas for applying drying gas, e.g., air, to the solid phase.
In yet another embodiment, the diagnostic device includes a removable label that can be pre-printed with diagnostic test information, and adapted to receive patient information and test result data. Once removed, this label can be placed in the patient""s medical file obviating the need for other manual or electronic transfer of the test data.
In another aspect of the invention, a method for conducting a diagnostic test, using the disposable diagnostic device described above, involves the steps of applying a sample to the solid phase, moving the solid phase along the channel by application of a first peristaltic force to the solid phase, moving a fluid from one compartment to the solid phase by application of a second peristaltic force to the compartment, allowing development of a diagnostic test result within the solid phase, and detecting the result. The first peristaltic force can be applied by movable dual pressures flanking the solid phase within the channel.
In preferred embodiments, the application of the second peristaltic force displaces fluid from the solid phase and the channel as the solid phase moves along the channel. The movement to and displacement from the solid phase can occur sequentially. As the movement and displacement occur, the fluid flow may change direction along the solid phase at least once as the solid phase moves along the channel. Generally, all fluids within the compartments are moved to the solid phase before detecting the result.
In other embodiments, the method involves the additional step of applying drying gas to the solid phase prior to detecting the result. Optionally, the solid phase can be agitated by moving the solid phase in a limited, repetitive back and forth motion within the channel.
When a label is included on the device, the method may also include the steps of recording test result data from the test result on a removable label adapted to receive the test data, recording patient information on the label prior to applying the sample, removing the label after the test result data have been recorded on it, and placing the label into the patient""s medical file.
As described herein, the present invention has many advantages. First, the device as formed from flexible films (1) can be used in several orientations, (2) isolates the solid phase while allowing for solid phase movement, (3) provides for formation of incubation, wash and read chambers simply by the external application of pressure to the channel, and (4) provides a minimal mean diffusion path between solid phase-bound materials and reactive reagents in the fluid contacting the solid phase. In addition, the device provides a completely sealed testing system containing premeasured and prepackaged reagents, thereby preventing contamination of the testing reagents. The invention also eliminates pipet/dilutor dispensers, provides a unique sample aliquoting device, and provides a one step sample application of a measured volume of sample. Movement of the solid phase within the testing device facilitates washing by eliminating the need to wash the walls of the chamber in addition to washing the solid phase. Reversing the direction of fluid flow along the solid phase also improves the washing step. The device can include a dual purpose vent system that allows displacement of air within the chambers, as well as introduction of air for purging and drying situations.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.